counter.re

type state = {
  count: int,
};

type action =
  | Add
  | Subtract;

module Counter = {  
  let component = ReasonReact.reducerComponent("Counter")

  let make = _children => {
    ...component,
    initialState: () => { count: 0 },
    reducer: (action, state) => {
    	switch (action) {
        | Add => ReasonReact.Update({ count: state.count + 1 })
        | Subtract => ReasonReact.Update({ count: state.count - 1 })
	  	}
    },
    render: self => {
      let message = "Count #" ++ string_of_int(self.state.count);

      <div>
        <div>(message |> ReasonReact.string)</div>
        <button onClick=(_event => Add |> self.send)>(ReasonReact.string("Add"))</button>
        <button onClick=(_event => Subtract |> self.send)>(ReasonReact.string("Subtract"))</button>
      </div>
    }
  };
};
      
ReactDOMRe.renderToElementWithId(<Counter />, "preview");